Period but no tissue

I had sex with a condom on February 13th. I got my period on time on February 26th, and it was normal except that it was just blood, there were no clots and no endometrial tissue or anything. It lasted for 7 days but for the past 2 weeks I've had to pee a lot more often than usual and now I'm worried that maybe that wasn't my period even though it was heavy and lasted 7 days. Is it normal to have a period and not notice any tissue? I usually notice it, and I thought the whole point of a period was to shed the tissue, so why didn't I see any?